Multifrequency tuning system



Aug. 16, 1949.

o. w. GREENE, JR 2,479,064

MULTIFREQUENCY TUNING SYSTEM Filed April 21, 1947 2 Sheets-Sheet l v 75 o c C; F61 j L 1 88 45765 2"! a; I g 13* B" SJ W Oliver WGz'eene Jr.

Aug. 16, 1949. o. w. GREENE, JR

MULTIFREQUENCY TUNING SYSTEM Filed April 21, 1947 2 Sheets-Sheet 2 52; If! M T K T 4 6 5%, 37 L 7 1 Olive? WGz'eene J2.

Patented Aug. 16, 1949 2,479,064 MULTIFREQUENCY TUNING SYSTEM Oliver W. Greene, Jr., Wakefield, R. I., assignor to Greene Plastics, Inc., a corporation of Rhode Island Application April 21, 1947, Serial No. 742,888

3 Claims.

tuning system and more particularly to a radiofrequency amplifier tank circuit with a switching across a single variable capacitance.

However, this arrangement has several disadvantages are present high circulating radio-frequency currents; and, in prior arrangements, it is noted that this circulating radio-frequency circuit is broken each time a new frequency of operation is selected.

One of the objects of this invention is to eliminate the breaking of any contact where there is present a high radio-frequency current.

Another object of this invention is to eliminate the breaking of any circuit Where there is present a high radio-frequency current by providing a permanent tank circuit with soldered low resistance connections.

Another object of this invention is to provide With these and other objects in view, the invention consists of certain novel features of construction as will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawings:

Fig. 1 is a diagrammatic view which the invention is located;

Fig. 2 is an end view of inductance and capacitance unit of the invention;

Fig. 3 is an elevation thereof with parts broken away;

Fig. 4 is an elevation of of contacts between which it is located;

Fig. 5 is an elevational detail on a larger scale of a portion of the showing of Fig. 3.

It is well known in the art that besides serving of a circuit in a fragmental portion the unit and the circuit in as means for transforming the actual load resist ance to the required value of plate load impedance to the tube, the plate tank circuit also should suppress the harmonics present in the tube output as inversely proportional to the plate voltage divided by the plate current ratio.

To reduce energy loss in the tank circuit, the

generally is or more. An unduly large L-C ratio is not advisable since it would result in a large circulating radio-frequency tank available for the load.

Referring to the drawings, I have shown, a double-tube, pus -pull radio-frequency amplifier circuit embodying this invention. It should be understood that this push-pull circuit is shown for purposes of illustration only, and this invention may be utilized in a single-tube radio-frequency amplifier circuit. The tank circuits which are particularly the subject matter of this invention are enclosed in dotted lines, being designated generally [5 and 25. Each of the tank circuits may be removed from the amplifier circuit as a whole by breaking the connection at the points Tl, T2, T3, T4 and T5 in [5, high radiowith the other group of plates. 54 is provided on the panel for rotating these Likewise, in tank circuit 25, high frequency alternating currents will be present through inductances Lg and capacitances C3 and C4 completed from stator plates 20 and 2| through permanently connected leads 22 and 23. The plate voltage will be shut off when changing bands of frequency.

The tank changing mechanism is shown in Figs. 2 and 3 where a suitable base is designated 30 from which there extend upwardly standards 3| and 32 to rotatably support a shaft 33 in bear-' ings at the upper ends of these? standards. I Upon this shaft, there is fixedly mounted a hub 34.

which has a plurality of radiating arms 35 each of which supports an inductor"'36 aridthe stator of a capacitor 31 which consists of a plurality of plates 38. These plates 38 are electricallyfconnected together by means of a bar which, in turn, is connected to the inductance coil.

The plates 38 are in-two sections, one section being connected to one end of the inductance coil asat 4E! and the other section being connected to the opposite end of the inductance coil as at 4|.

The inductor 36 is also formed in two sections, the inner ends of the two sections being suitably connected together.

A link coil 42 or 43 is positioned between the two sections. A bar 45 of insulating material carries five contacts Tl, T2,

T3, T4 and T5 which are connected to the inductor and capacitor of the tank circuit as shown in the diagrammatic view in Fig. 1.

The contacts TI and T2 have wiping engagement with the spring arms46, 41 which are connected tothe tube plates, contact T3 which leads to the mid connector of the two inductor sections wipes arm %8-which is connected to the high voltage supply,

and contacts T4 and T5 run to the ends of the link (i2 and engage contacts 49, 49 which are connected to the antenna. This latter group is mounted on an insulating block held stationary or in a fixed position so that the contacts T3, T4

and T5 will wipingly engage these resilient arms as the tank is rotated into position. The tank 25 is connected in the same manner as the tank [5 above described.

The rotor of the capacitor, indicated diagram- -matically at Cl and C2 (see Fig. 1), comprises a shaft 58 (see Fig. 3) which is rotatably mounted inbearings 53 on the standards or supports 3| A,

" with said second assembly thereby forming a plates are provided in two groups, one group to interleave with one group of plates, while the other group of plates is positioned to interleave A suitable knob plates so that tuning may be had Within the 'band spread provided by the tank circuit above described.

Upon each of the radial arms 35, there will be mounted an inductor'st and a capacitor stator 31 which together form-a unit for a particular band spread. I have illustrated five such tanks which forthe amateur range may be in frequencies of 10, 15, 20, i and 80.

Each inductor and capacitor "36 and 3'i will been adjusted to provide the proper L-C ratio which will be most efiicient for operation of this band spread. But one of these units; however, will be utilized at one time, and inorder that one may be substituted for another,

I may merely rotate the shaft 33 so as to position the desired unit in operating relation with the rotor of the capacitor consisting of the plates on the shaft 50; and, when in such a position 5 that the stator plates of the capacitor interleave with the rotor plates of the capacitor, tuning in the band range may be had by rotation of the .shaft 50 from the knob54 on the panel.

In order to easily rotate the shaft 33, I have loprovided a gear 55 which is fixed on the shaft "and which meshes with a small gear 56 on shaft flel which hasra crank 58 with handle 59; so that, as this crank, is rotated, the shaft 33 will be irotatedqfor suitably'pOsitioning the desired unit 1'5"tothat"the statoriwill be in interleaving relation with the rotor. "In order to register each unit in .position, I have provided a spring pin 60 to extend into a suitable recess in the gear 55. A spring 6| forces this pin outwardly; but, as it has a rounded nose, an increased force will dislodge it from position for further movement of the gear.

I claim:

1. multi'range'tuning device comprising a base plate, two inverted V-shaped members mounted a fixed distance apart on said base filatatwo-bearings affixed to the apex of said -Vshaped-members, a first assembly comprising a first shaft mounted in said bearings, a plurality of center tapped induetances mounted radially about said shaft on an axis parallel to the axis of said shaft and at an equal distance thereto, aplura-lity of mounting strips substantially the length of said inductances having perpendicularly mounted thereon andat each end thereof a group of spaced stator plates, each mounting strip being positioned on the periphery of each inductance and on an axis-parallel to said shaft, each respective group of said stator plates being electrically connected together and to a separate end of each of said inductances, a second assembly comprising a second shaft rotatably mounted within the area bounded by said base plate and the inverted V-shapedmembers on adjacent legs of said inverted v members and on an axis parallel to said firstshaft, two groups of spaced rotor plates mechanicallyand electrically affixed perpendicularly on said secon'ds'naft and so positioned on said shaft so as to mesh with said stator plates when the'i'irst assembly is rotated into position '3. 'Adevi ce as claimed in claim 1, wherein there are-a plurality of five prong plugs physically associated with each of said inductances and stator plates, to provide an electrical connection to-external circuits.

OLIVER W. GREENE, JR.

REFERENCES GITED 'The'followingreferences are of record in the file of this patent:

UNITED STATES PATENTS Name Date Chunn May 5, 1936 Garthwaite -Sept.- 18, 1945 Number 

